Flora of the Palouse Region 55 



pistillate flowers 2-3 (rarely 1) in the axil of each bract: perianth 

 none: ovary sessile, 2 -celled: nut small, a samara, shorter than 

 the bracts. 



Three species occur within our limits, none of which seem to be 

 named at the date of writing, though two of them have frequently 

 been mentioned in publications under wrong names. 



B. Tree with a single trunk, 8-20 m. high, erect: 



bark grayish-bronze, the erect or spreading branchlets a dull gray: leaves 

 broadly ovate, attenuate-acute at base, somewhat lobed at the ends of the 

 prominent nerves, serrate, acuminate, very sparsely hairy on both sides, 

 scarcely glandular, 4-7 cm. long, on slender petioles 2-3 cm. long: pistdlate 

 aments cylindrical, 3 cm. long, 1 cm. thick, usually drooping on slender 

 peduncles: bracts pubescent, the central lobes longest. Thatuna Hills, not 

 common. 



/ ' 

 B. Small tree, 5-8 m. high, the several trunks rarely 



erect, the bark dark bronze; branchlets drooping, grayish, warty: leaves 

 broadly ovate, obtuse or acute, coarsely serrate-dentate, glandular and 

 sparsely hairy on each surface, 2-4 cm. long, on slender petioles half their 

 length ^staminate aments about 2 cm. long: pistillate aments solitary, cylin- 

 dric, 2-3 cm. long, drooping with the branchlets, sessile or on short pedun- 

 cles: fruiting bracts pubescent and ciliolate, the central lobe largest and 

 narrowest: wings as broad as the obovate nutlet. Along streams eight miles 

 southwest of Pullman. 



B. Graceful tree, 8-15 m. tall, with drooping 



branches: bark dark bronze, even the branchlets scarcely gray, these latter 

 very glandular: leaves ovate, obtuse or acute at the base, coarsely doubly 

 serrate, acuminate, shining green above, glandular on both surfaces, 2-4 

 cm. long, on petioles half as long: pistillate aments cylindrical: 5 cm. long, 

 .5 cm. thick, often flexuous, mostly in twos, dark green: staminate aments 

 narrow, flexuous, 4-8 cm. long. Springy hillsides near Almota. 



85. ALNUS. 



Trees or shrubs: leaves dentate or serrulate: buds few-scaled: 

 both kinds of flowers in aments, expanding before, with or after 

 the leaves; the staminate pendulous; the pistillate erect, clustered: 

 staminate flowers 3, sometimes 6, in the axil of each bract, con- 

 sisting of a mostly 4-parted perianth and 4 stamens, and subtended 

 by 1 or 2 bractlets; filaments short, simple; anther-sacs adnate: 

 pistillate flowers 2-3 in the axil of each bract, without a perianth, 

 but subtended by 2-4 minute bractlets: ovary sessile, 2-celled; 

 styles 2: bracts woody, persistent, 5 -toothed or erose: nut small, 

 compressed, wingless or winged. 



Leaves simply denticulate, not at all lobed. A. RHOMBIFOUA. 



Leaves doubly dentate or with short lobes at the ends of the main veins. 



Peduncles slender, exceeding the cones. A. sinuata. 



Peduncles stout, shorter than the cones. \. tknt]Koi,ia. 



